Automatic fire extinguishers are well known and have been in use for many years. For example a U.S. Patent of Davios et al., U.S. Pat. No. 4,718,498 discloses a flame sensing device connected to a supply of electric current to an electromagnet to release the fire extinguishing fluid to extinguish a fire. The flame sensing device includes a first spring which extends when heated, and a second spring in compression acting to pull an end of the first spring to close a contact to thereby provide electric current to the electromagnet.
A more recent patent of Brim, U.S. Pat. No. 5,458,201 discloses an adapter for a fire extinguisher that is mountable to a valve assembly of a conventional fire extinguisher to form a portable automatic fire extinguisher. The adapter comprises a coupling which is mountable to the valve assembly, an elongate conduit and an automatic sprinkler head. When the adapter is mounted to the fire extinguisher the sprinkler head is placed in fluid communication with the fire extinguisher and is locatable adjacent a ceiling of a room. If a fire occurs in the room the automatic sprinkler head releases fluid from the fire extinguisher onto the floor of the room.
A still further approach to automatic fire extinguishers is disclosed in a United States Patent of Schmidt, U.S. Pat. No. 5,771,977. The Schmidt patent discloses an adapter to a trigger mechanism of a conventional fire extinguisher to form a portable automatic fire extinguisher. The adapter comprises a compressed spring held in place with a heat release fusible link. If a fire occurs in the vicinity of the adapter, the fusible link separates allowing the compression spring to depress the fire extinguisher trigger mechanism.
Notwithstanding the above it is presently believed that there may be a need and a potential commercial market for an automatic fire extinguisher in accordance with the present invention. There may be a need and a commercial market because such extinguishers have a relative simple design, should be relatively inexpensive to manufacture and sell, durable and relatively easily to refill and recharge. In addition, the automatic fire extinguisher in accordance with the present invention is self-righting and heat activatible.